Material requirements for API standard 650 welded storage tanks

The establishment of a correct method for evaluating the life of API standard 650 welded storage tanks requires the preparation of criteria related to the strength and cracks of API standard 650 welded storage tanks, mechanical damage mechanisms, corrosion mechanisms, and mathematical models of fatigue crack growth, etc., which are compiled into computer programs. In the process of programming the program, it is required to select the operating parameters, plates, reinforcement accessories, metal properties, corrosion levels, mechanical damage defects and other data of the oil storage tank under various conditions.

Allowable compressive stresses shall be in accordance with 5.5.4 except that for aluminum alloy plate the allowable compressive stresses shall be reduced by the ratio of the modulus of compressive elasticity to 29,000 for values of (t – c)/R less than 0.0175 and by the ratio of the minimum yield strength for the aluminum alloy in question to 30,000 for values of (t – c)/R equal to or greater than 0.0175 (see 5.5.2 for definitions). In all other equations in this standard API standard 650 welded storage tanks where yield strength or modulus of elasticity is used, such as Equations 27 and 28, similar corrections shall be made for aluminum alloys.

API 650 internal floating roof oil tank is a volatile liquid storage tank with a combination of a dome tank and an internal floating roof structure, which is a floating roof assembled under the dome of the API standard 650 welded storage tanks storage tank. The combination of the vault roof outside the API 650 storage tank and the floating roof inside the tank has been widely used in gasoline, aviation kerosene and more volatile chemical liquids.